mat-button Rectangular text button w/ no elevation
mat-raised-button Rectangular contained button w/ elevation
mat-flat-button Rectangular contained button w/ no elevation
mat-stroked-button Rectangular outlined button w/ no elevation
mat-icon-button Circular button with a transparent background, meant to contain an icon
mat-fab Circular button w/ elevation, defaults to theme's accent color
mat-mini-fab Same as mat-fab but smaller